Light-emitting device

ABSTRACT

A substrate (100) is a light-transmitting substrate. A light-transmitting first electrode (110) is formed over the substrate (100). An insulating layer (150) is formed over the substrate (100) and the first electrode (110) and includes an opening (152) overlapping the first electrode (110). An organic layer (120) is located within at least the opening (152). A light-transmitting second electrode (130) is formed over the organic layer (120). An intermediate layer (200) is formed in at least a portion of a region of a lateral side of the first electrode (110) overlapping the first electrode (110). A refractive index of the intermediate layer (200) is between a refractive index of the substrate (100) and a refractive index of the first electrode (110).

RELATED APPLICATION INFORMATION

This application is a continuation of application Ser. No. 16/730,781filed on Dec. 30, 2019, which is a continuation of application Ser. No.16/221,352 filed on Dec. 14, 2018, now U.S. Pat. No 10,553,828, issuedon Feb. 4, 2020, which is a continuation of application serial number15/560,967 filed Sep. 22, 2017, now U.S. Pat. No: 10,186,687, issued onJan. 22, 2019, which is a National Stage Entry of InternationalApplication No. PCT/JP2015/059240 filed on Mar. 25, 2015, and thedisclosures of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to a light-emitting device. BACKGROUND ART

In recent years, there has been progress in the development oflight-emitting devices using an organic EL element as a light-emittingunit. The organic EL element has a configuration interposing an organiclayer between a first electrode and a second electrode. Such alight-emitting device may require transparency depending on itsapplication. In order to make the light-emitting device transparent, thefirst electrode and the second electrode may be formed of a transparentconductive material.

On the other hand, in a case where the light-emitting device is madetransparent, the edge of an electrode of an organic EL element maybecome conspicuous. In consideration thereof, Patent Document 1discloses providing a correction layer in a region where no cathode isformed, the correction layer having the same material and thickness asthose of the cathode. As an example of the cathode, a thin film of ametal such as magnesium, aluminum, or calcium having a low work functionis disclosed. The correction layer is formed on the cathode with aninsulating layer interposed therebetween.

Meanwhile, Patent Document 2 discloses a substrate provided with atransparent electrode, composed of a refractive index control layer anda transparent electrode layer formed in order on a transparentsubstrate. In Patent Document 2, the average refractive index of therefractive index control layer is 1.45 to 1.60. In addition, therefractive index control layer is formed as a laminate of two or morekinds of layers, the entire film thickness being 1,000 to 2,500 nm.

RELATED DOCUMENTS Patent Documents

[Patent Document 1]: Japanese Unexamined Patent Application PublicationNo. 2002-270377

[Patent Document 2] Japanese Unexamined Patent Application PublicationNo. 2014-198423

SUMMARY OF THE INVENTION Technical Problem

According to Patent Document 2, non-visibility of the transparentelectrode layer, when seen from the transparent substrate side, isimproved by the refractive index control layer. However, in general, aninsulating layer and an electrode forming a light-emitting unit havedifferent refractive indexes. For this reason, the refractive indexdifference at an interface between the refractive index control layerand the insulating layer, and the refractive index difference at aninterface between the refractive index control layer and the electrodeare different from each other. Therefore, when viewed from a sideopposite to the transparent substrate side, the edge of the electrodemay become conspicuous.

The exemplified problem to be solved by the present invention is torender an edge of an electrode less conspicuous when seen from a sideopposite to a transparent substrate side and to prevent reduction inlight extraction efficiency of a light-emitting device.

Solution to the Problem

According to the invention of claim 1, there is provided alight-emitting device including:

a light-transmitting substrate;

a light-transmitting interconnect positioned over the substrate;

-   -   an insulating layer positioned over the substrate and the        interconnect; and

an intermediate layer positioned in at least a portion of a region of alateral side of the interconnect that overlaps the insulating layer,

wherein a refractive index of the intermediate layer is between arefractive index of the interconnect and a refractive index of theinsulating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages will be madeclearer from certain preferred embodiments described below, and thefollowing accompanying drawings.

FIG. 1 is a plan view illustrating a configuration of a light-emittingdevice according to an embodiment.

FIG. 2 is a diagram in which a partition wall, an insulating layer, anda second electrode are removed from FIG. 1.

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 1.

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 1.

FIG. 5 is a cross-sectional view taken along line C-C of FIG. 1.

FIG. 6 is a cross-sectional view illustrating a configuration of alight-emitting device according to a second embodiment.

FIG. 7 is a cross-sectional view illustrating a configuration of thelight-emitting device according to the second embodiment.

FIG. 8 is a cross-sectional view illustrating a configuration of thelight-emitting device according to the second embodiment.

FIG. 9 is a plan view illustrating a configuration of a light-emittingdevice according to a third embodiment.

FIG. 10 is a plan view illustrating a configuration of thelight-emitting device according to the third embodiment.

FIG. 11 is a cross-sectional view illustrating a configuration of thelight-emitting device according to the third embodiment.

FIG. 12 is a cross-sectional view illustrating a configuration of thelight-emitting device according to the third embodiment.

FIG. 13 is a cross-sectional view illustrating a configuration of thelight-emitting device according to the third embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be describedwith reference to the accompanying drawings. In all the drawings, likeelements are referenced by like reference numerals and the descriptionsthereof will not be repeated. In addition, in the following description,having a light-transmitting property, being light-transmitting, ortransmitting light means transmitting at least visible light.

FIG. 1 is a plan view illustrating a configuration of a light-emittingdevice 10 according to an embodiment. FIG. 2 is a diagram in which apartition wall 170, an insulating layer 150, and a second electrode 130are removed from FIG. 1. FIG. 3 is a cross-sectional view taken alongline A-A of FIG. 1, FIG. 4 is a cross-sectional view taken along lineB-B of FIG. 1, and FIG. 5 is a cross-sectional view taken along line C-Cof FIG. 1.

The light-emitting device 10 according to the embodiment includes asubstrate 100, a first electrode 110, an insulating layer 150, anorganic layer 120, a second electrode 130, and an intermediate layer200. The substrate 100 is light-transmitting. The first electrode 110 isformed on the substrate 100 and has a light-transmitting property. Theinsulating layer 150 is formed over the substrate 100 and the firstelectrode 110 and includes an opening 152 overlapping the firstelectrode 110. The organic layer 120 is located within at least theopening 152. The second electrode 130 is formed over the organic layer120 and has a light-transmitting property. The intermediate layer 200 isformed in at least a portion of a region of the lateral side of thefirst electrode 110 which overlaps the insulating layer 150. Therefractive index of the intermediate layer 200 is between the refractiveindex of the first electrode 110 and the refractive index of theinsulating layer 150.

In addition, the light-emitting device 10 includes an interconnect 116.The interconnect 116 is formed on the substrate 100 and has alight-transmitting property. The insulating layer 150 is formed also onthe interconnect 116. The intermediate layer 200 is formed in at least aportion of a region of the lateral side of the interconnect 116 whichoverlaps the insulating layer 150. The refractive index of theintermediate layer 200 is between the refractive index of theinterconnect 116 and the refractive index of the insulating layer 150.Hereinafter, a detailed description will be given.

The light-emitting device 10 according to the embodiment is a displaydevice, and includes the substrate 100, the first electrode 110, pluralfirst terminals 112, plural second terminals 132, a light-emitting unit140, the insulating layer 150, plural openings 152, plural openings 154,plural lead-out interconnections 114, the organic layer 120, the secondelectrode 130, plural lead-out interconnections 134, and pluralpartition walls 170.

The substrate 100 is formed of a light-transmitting material such as,for example, a glass or a light-transmitting resin. The substrate 100 ispolygonal such as, for example, rectangular. The substrate 100 may haveflexibility. In a case where the substrate 100 has flexibility, thethickness of the substrate 100 is, for example, equal to or greater than10 μm and equal to or less than 1,000 μm. Particularly, in a case wherethe substrate 100 is formed of glass, the thickness of the substrate 100is, for example, equal to or less than 200 μm. In a case where thesubstrate 100 is a resin, the substrate 100 is formed using, forexample, polyethylene naphthalate (PEN), polyether sulphone (PES),polyethylene terephthalate (PET), or polyimide. In addition, in a casewhere the substrate 100 is a resin, an inorganic barrier film of SiNx,SiON or the like is formed on at least one surface (preferably, bothsurfaces) of the substrate 100 in order to prevent moisture frompermeating the substrate 100. In a case where the substrate 100 is aglass substrate, the refractive index n₁ of the substrate 100 is, forexample, equal to or greater than 1.4 and equal to or less than 1.6.

The light-emitting unit 140 is formed on the substrate 100 and includesan organic EL element. The organic EL element has a configuration inwhich the first electrode 110, the organic layer 120, and the secondelectrode 130 are laminated in this order.

The first electrode 110 is a transparent electrode which is formed onthe substrate 100 and has a light-transmitting property. A transparentconductive material constituting the transparent electrode is a materialincluding a metal, for example, a metal oxide such as an indium tinoxide (ITO), an indium zinc oxide (IZO), an indium tungsten zinc oxide(IWZO), or a zinc oxide (ZnO). The thickness of the first electrode 110is, for example, equal to or greater than 10 nm and equal to or lessthan 500 nm. The first electrode 110 is formed using, for example,sputtering or vapor deposition using a mask. Meanwhile, the firstelectrode 110 may be a thin metal material (for example, Ag or an Agalloy), carbon nanotubes, or a conductive organic material such asPEDOT/PSS. The refractive index n₂ of the first electrode 110 is greaterthan the refractive index n₁ of the substrate 100, and is, for example,equal to or greater than 1.8 and equal to or less than 2.2.

The first electrode 110 linearly extends in a first direction (Ydirection in FIGS. 1 and 2). An end of the first electrode 110 iselectrically and physically connected to the lead-out interconnection114. The lead-out interconnection 114 is formed using the same materialas that of the first electrode 110. Therefore, the lead-outinterconnection 114 is light-transmitting. In the present example, thelead-out interconnection 114 is formed integrally with the firstelectrode 110. The lead-out interconnection 114 is connected to thefirst terminal 112. In the example shown in the drawing, the end of thelead-out interconnection 114 serves as the first terminal 112.

The insulating layer 150 is formed over conductor patterns serving asplural first electrodes 110 and over the substrate 100 between the firstelectrodes 100. The insulating layer 150 partially covers the uppersurfaces of the conductor patterns serving as the first electrodes 110.The insulating layer 150 is formed using a photosensitive resinmaterial, such as, for example, a light-transmitting polyimide-basedresin. The insulating layer 150 may be formed using resins other thanthe polyimide-based resin, for example, an epoxy-based resin or anacrylic-based resin. The refractive index n₃ of the insulating layer 150exists between the refractive index n₁ of the substrate 100 and therefractive index n₂ of the first electrode 110, and is, for example,equal to or greater than 1.6 and equal to or less than 1.8.

The second electrode 130 is formed on the organic layer 120. Similarlyto the first electrode 110, the second electrode 130 is a transparentelectrode having a light-transmitting property. A material exemplifiedas the material constituting the first electrode 110 may be used in amaterial constituting the second electrode 130. However, the firstelectrode 110 and the second electrode 130 may be formed using differentmaterials or may be formed using the same material. In addition, thefilm thickness of the second electrode 130 and a method of forming thesecond electrode 130 are the same as the film thickness of the firstelectrode 110 and a method of forming the second electrode 130. However,the film thickness of the second electrode 130 may be different from thefilm thickness of the first electrode 110.

The second electrode 130 extends in a second direction (X direction inFIG. 1) intersecting the first direction. The partition wall 170 isformed between the second electrodes 130 next to each other. Thepartition wall 170 extends parallel to the second electrode 130, thatis, in the second direction, and is provided in order to separate thesecond electrodes 130 from each other.

Specifically, the partition wall 170 is formed in a shape which istrapezoidal in cross-section and is turned upside down (invertedtrapezoid). That is, the width of the upper surface of the partitionwall 170 is larger than the width of the lower surface of the partitionwall 170. For this reason, when the partition wall 170 is formed priorto the second electrode 130, plural second electrodes 130 may becollectively formed by forming the second electrodes 130 on one surfaceside of the substrate 100 by vapor deposition or sputtering. Inaddition, the partition wall 170 also has a function of partitioning theorganic layer 120.

The foundation of the partition wall 170 is, for example, the insulatinglayer 150. The partition wall 170 is, for example, a photosensitiveresin such as a polyimide-based resin, and is formed in a desiredpattern by exposure and development. Meanwhile, the partition wall 170may be formed of a resin other than a polyimide-based resin, forexample, an epoxy-based resin or an acrylic-based resin, or an inorganicmaterial such as silicon dioxide.

Meanwhile, the light-emitting device 10 is not required to include thepartition wall 170. In this case, the second electrode 130 is formed ina predetermined pattern by using a mask during sputtering or vapordeposition.

In addition, plural openings 152 and plural openings 154 are formed inthe insulating layer 150. The opening 152 is located at the point ofintersection of the first electrode 110 and the second electrode 130, ona surface parallel to the substrate 100. Specifically, the pluralopenings 152 are aligned in the extending direction of the firstelectrode 110 (Y direction in FIG. 1). In addition, the plural openings152 are also aligned in the extending direction of the second electrode130 (X direction in FIG. 1). For this reason, the plural openings 152are arranged to constitute a matrix.

The organic layer 120 is formed in a region overlapping the opening 152.The organic layer 120 includes a light-emitting layer. Therefore, thelight-emitting unit 140 is located in each region overlapping theopening 152.

Specifically, the organic layer 120 has a configuration in which, forexample, a hole injection layer, a light-emitting layer, and an electroninjection layer are laminated. A hole transport layer may be formedbetween the hole injection layer and the light-emitting layer. Inaddition, an electron transport layer may be formed between thelight-emitting layer and the electron injection layer. The organic layer120 may be formed by vapor deposition. In addition, at least one layerof the organic layer 120, for example, a layer in contact with the firstelectrode 110, may be formed by a coating method such as an ink jetting,printing, or spraying. Meanwhile, in this case, the remaining layers ofthe organic layer 120 are formed by vapor deposition. In addition, alllayers of the organic layer 120 may be formed by coating. The holeinjection layer of the organic layer 120 is in contact with the firstelectrode 110, and the electron injection layer of the organic layer 120is in contact with the second electrode 130.

Meanwhile, in the examples shown in FIGS. 3 and 4, a case is shown inwhich each of layers constituting the organic layer 120 all protrude tothe outside of the opening 152. As shown in FIG. 4, the organic layer120 may or may not be continuously formed between the openings 152 nextto each other in the extending direction of the partition wall 170.However, as shown in FIG. 5, the organic layer 120 is not formed in theopening 154.

In addition, as described above, the light-emitting unit 140 is locatedin each region overlapping the opening 152. Therefore, to be exact, asshown in FIG. 3, the first electrode 110 may be defined as a region ofthe conductor pattern serving as the first electrode 110 which overlapsthe opening 152, in the extending direction of the conductor patternserving as the first electrode 110. In the first electrode 110 accordingto this definition, the edges of the upper surface of the firstelectrode 110 in a width direction (both ends of the first electrode 110in FIG. 4) are covered by the insulating layer 150. A portion of theconductor pattern serving as the first electrode 110 which is locatedbetween the first electrodes 110 next to each other may be defined asthe interconnect 116. The interconnect 116 is covered by the insulatinglayer 150.

The opening 154 is located in a region overlapping one end side of eachof the plurality of second electrodes 130 when seen in a plan view. Inaddition, the opening 154 is disposed along one side of the matrixconstituted by the openings 152. When seen in a direction along the oneside (for example, Y direction in FIG. 1, that is, the direction alongthe first electrode 110), the openings 154 are disposed at apredetermined interval. A portion of the lead-out interconnection 134 isexposed from the opening 154. The lead-out interconnection 134 isconnected to the second electrode 130 through the opening 154.

The lead-out interconnection 134 is for electrically connecting thesecond electrode 130 to a second terminal 132, and includes a layerconstituted of the same material as that of the first electrode 110. Oneend side of the lead-out interconnection 134 is located below theopening 154, and the other end side of the lead-out interconnection 134is extracted to the outside of the insulating layer 150. In the examplesshown in the drawings, the other end side of the lead-outinterconnection 134 serves as the second terminal 132.

A conductive member such as a flexible printed circuit (FPC) isconnected to the first terminal 112 and the second terminal 132. In theexample shown in the drawings, the first terminal 112 and the secondterminal 132 are disposed along the same side of the substrate 100.Therefore, in a case where the FPC is used as a conductive member, thefirst terminal 112 and the second terminal 132 can be connected to oneFPC.

In addition, the light-emitting device 10 includes the intermediatelayer 200. The intermediate layer 200 is formed in at least a portion(preferably, the entirety) of a region of the lateral side of the firstelectrode 110 which overlaps the insulating layer 150, and at least aportion (preferably, the entirety) of a region of the lateral side ofthe interconnect 116 which overlaps the insulating layer 150. In theexample shown in the drawings, the intermediate layer 200 is also formedon the lateral side of the first terminal 112, the lateral side of thelead-out interconnection 114, the lateral side of the second terminal132, and the lateral side of the lead-out interconnection 134. Thethickness of the intermediate layer 200 is, for example, equal to orgreater than 50 nm and equal to or less than 500 nm.

The refractive index n₄ of the intermediate layer 200 is between therefractive index n₂ of the first electrode 110 and the refractive indexn₃ of the insulating layer 150. In order to achieve such aconfiguration, the intermediate layer 200 may be formed using, forexample, both a material constituting the first electrode 110 and amaterial constituting the insulating layer 150. In this case, the volumecontent of the material same as that of the first electrode 110 in theintermediate layer 200 is, for example, equal to or greater than 30% andequal to or less than 70%. Meanwhile, the volume content of the materialsame as that of the first electrode 110 may be replaced with, forexample, the area ratio of the material same as that of the firstelectrode 110 in a cross-sectional photograph of the intermediate layer200.

In addition, the intermediate layer 200 may be formed using a materialcontaining silicon, oxygen, and nitrogen, such as a silicon oxynitride.In this case, the ratio of the nitrogen content of the intermediatelayer 200 to the oxygen content of the intermediate layer 200 is, forexample, equal to or greater than 2 and equal to or less than 9.Meanwhile, the ratio can also be replaced with, for example, the ratioof peak heights in X-ray fluorescence (XRF) or energy dispersive X-rayspectroscopy (EDX).

Next, a method of manufacturing the light-emitting device 10 in thepresent embodiment will be described. First, the first electrode 110,the interconnect 116, the first terminal 112, the second terminal 132,and the lead-out interconnections 114 and 134 are formed over thesubstrate 100. These components are formed by, for example, sputteringor vapor deposition using a mask. However, these components may beformed using other methods.

Next, the intermediate layer 200 is formed on the lateral side of thefirst electrode 110, the lateral side of the first terminal 112, thelateral side of the second terminal 132, the lateral side of theinterconnect 116, and the lateral sides of the lead-out interconnections114 and 134. In a case where the intermediate layer 200 is formed usinga material constituting the first electrode 110 and a materialconstituting the insulating layer 150, the intermediate layer 200 isformed by, for example, coating a material constituting the firstelectrode 110, coating a material constituting the insulating layer 150,and then heat-treating the materials. Meanwhile, the intermediate layer200 may alternatively be formed by mixing the coating material includingthe material constituting the first electrode 110 and the coatingmaterial constituting the insulating layer 150 in advance, and coatingand heat treating the mixed material.

In addition, in a case where the intermediate layer 200 is formed usinga material containing silicon, oxygen, and nitrogen, the intermediatelayer 200 is formed using a gas phase method such as CVD or alithographic method.

Next, a photosensitive insulating film serving as the insulating layer150 is formed over the substrate 100 and the first electrode 110 using,for example, a coating method. Thereafter, the insulating film isexposed and developed, thereby forming the insulating layer 150. In thisprocess, the openings 152 and 154 are also formed. Thereafter, thepartition wall 170, the organic layer 120, and the second electrode 130are formed in this order.

In the present embodiment, the substrate 100, the first electrode 110,and the second electrode 130 are light-transmitting. Therefore, thelight-emitting device 10 serves as a transparent display. However, sincethe refractive index n₂ of the first electrode 110 and the refractiveindex n₃ of the insulating layer 150 are different from each other,light is scattered on the interface between the lateral side of thefirst electrode 110 and the insulating layer 150. As a result, there isthe possibility of a user noticing the edge of the first electrode 110.On the other hand, in the present embodiment, at least a portion(preferably, the entirety) of a region of the lateral side of the firstelectrode 110 which faces the insulating layer 150 is covered by theintermediate layer 200. The refractive index n₄ of the intermediatelayer 200 exists between the refractive index n₂ of the first electrode110 and the refractive index n₃ of the insulating layer 150. For thisreason, light is less likely to be scattered between the lateral side ofthe first electrode 110 and the insulating layer 150 than in a casewhere the intermediate layer 200 is not provided, and thus a user isless likely to notice the edge of the first electrode 110.

In addition, the intermediate layer 200 is also formed on the lateralside of the interconnect 116, the lateral side of a portion of thelead-out interconnection 114 which is covered by the insulating layer150, and the lateral side of a portion of the lead-out interconnection134 which is covered by the insulating layer 150. Therefore, light isalso less likely to be scattered between each of these lateral sides andthe insulating layer 150. Therefore, a user is less likely to notice theedge of the interconnect 116, the edge of the lead-out interconnection114, and the edge of the lead-out interconnection 134.

Second Embodiment

FIGS. 6, 7, and 8 are cross-sectional views of a light-emitting device10 according to a second embodiment, and correspond to FIGS. 3, 4, and 5in the first embodiment, respectively.

The light-emitting device 10 according to the present embodiment has thesame configuration as that of the light-emitting device 10 according tothe first embodiment, except for the layout of the intermediate layer200.

In the present embodiment, similarly to the first embodiment, theinsulating layer 150 covers the edges of the upper surface of the firstelectrode 110 in a width direction (both ends of the first electrode 110in FIG. 7). As shown in FIGS. 6 and 7, the intermediate layer 200 isformed on at least a portion (preferably, the entirety) of a region ofthe upper surface of the first electrode 110 which is covered by theinsulating layer 150.

In addition, as shown in FIG. 6, the intermediate layer 200 is formed inat least a portion of a region of the upper surface of the interconnect116 which is covered by the insulating layer 150. In the examples shownin FIGS. 6 and 7, on a cross-section in a direction (Y direction ofFIG. 1) orthogonal to the extending direction of the interconnect 116,the insulating layer 150 and the intermediate layer 200 are formed onthe entirety of the interconnect 116. In other words, the intermediatelayer 200 is formed on the entirety of a region of the interconnect 116which is covered by the insulating layer 150.

In addition, as shown in FIG. 8, the intermediate layer 200 is formed onthe entirety of a region of the lead-out interconnection 134 covered bythe insulating layer 150. Similarly, the intermediate layer 200 isformed on the entirety of a region of the lead-out interconnection 114covered by the insulating layer 150.

In the present embodiment, a user is also less likely to notice the edgeof the first electrode 110, the edge of the interconnect 116, the edgeof the lead-out interconnection 114, and the edge of the lead-outinterconnection 134. In addition, since the intermediate layer 200 isalso formed on the upper surfaces of the first electrode 110, theinterconnect 116, the lead-out interconnection 114, and the lead-outinterconnection 134, the degree of accuracy required for the position ofthe intermediate layer 200 is reduced, allowing the manufacturing costof the light-emitting device 10 to be reduced.

Meanwhile, in the first and second embodiments, the intermediate layer200 may be formed over portions of the substrate 100, including aportion of the substrate 100 located in the vicinity of the firstelectrode 110, a portion thereof located in the vicinity of the firstterminal 112, a portion thereof located in the vicinity of the lead-outinterconnection 114, a portion thereof located in the vicinity of theinterconnect 116, a portion thereof located in the vicinity of thesecond terminal 132, and a portion located in the vicinity of thelead-out interconnection 134.

Third Embodiment

FIGS. 9 and 10 are plan views illustrating a configuration of alight-emitting device 10 according to a third embodiment. FIGS. 11, 12,and 13 are cross-sectional views illustrating a configuration of thelight-emitting device 10. FIGS. 9 to 13 correspond to FIGS. 1 to 5 inthe embodiment.

The light-emitting device 10 according to the present embodiment has thesame configuration as that of the light-emitting device 10 according tothe first embodiment, except that the intermediate layer 200 is alsoprovided on a surface of the substrate 100 where the light-emitting unit140 is formed. Therefore, the intermediate layer 200 is formed in atleast a portion (the entirety in the example shown in the drawing)between the substrate 100 and the first electrode 110, at least aportion (the entirety in the example shown in the drawing) between thesubstrate 100 and the interconnect 116, at least a portion (the entiretyin the example shown in the drawing) between the insulating layer 150located next to the first electrode 110 and the substrate 100, at leasta portion (the entirety in the example shown in the drawing) between theinsulating layer 150 located next to the interconnect 116 and thesubstrate 100, at least a portion (the entirety in the example shown inthe drawing) between the substrate 100 and the lead-out interconnection114, and at least a portion (the entirety in the example shown in thedrawing) between the substrate 100 and the lead-out interconnection 134.The refractive index n₄ of the intermediate layer 200 formed on thesubstrate 100 exists between the refractive index n₁ of the substrate100 and the refractive index n₂ of the first electrode 110.

More specifically, the refractive index n₃ of the insulating layer 150is preferably between the refractive index n₂ of the first electrode 110and the refractive index n₁ of the substrate 100, and the refractiveindex n₄ of the intermediate layer 200 is preferably between therefractive index n₂ of the first electrode 110 and the refractive indexn₃ of the insulating layer 150. In addition, n₄ is preferably between√(n₁×n₂) and (n₂+n₃)/2. Further, when the wavelength of a maximum peakof an emission spectrum of the organic layer 120 is λ, and the thicknessof the intermediate layer 200 is d, 0.9λ/4≤n₄×d≤1.1λ/4 and√(n₁×n₂)≤n₄≤(n₂+n₃)/2 are preferably true.

Meanwhile, a material of the intermediate layer 200 formed on thesubstrate 100 is the same as a material of the intermediate layer 200shown in the first embodiment. However, the intermediate layer 200formed on the substrate 100 may be different from that of theintermediate layer 200 covering the lateral side of the first electrode110. In addition, the thickness of the intermediate layer 200 formed onthe substrate 100 is, for example, equal to or greater than 50 nm andequal to or less than 500 nm.

According to the present embodiment, the intermediate layer 200 isformed between the first electrode 110 and the substrate 100. Therefractive index n₄ of the intermediate layer 200 exists between therefractive index n₁ of the substrate 100 and the refractive index n₂ ofthe first electrode 110. Therefore, extraction efficiency of light fromthe organic layer 120 is further improved than in a case where nointermediate layer 200 is provided. In a case where n₄ is √(n₁×n₂), theextraction efficiency of light from the organic layer 120 is furtherimproved. In addition, in a case where 0.9λ/4≤n₄×d≤1.1λ/4 is true and n₄is I(n₁×n₂), extraction efficiency of light from the organic layer 120is further improved.

In addition, since the refractive index n₄ of the intermediate layer 200is between the refractive index n₂ of the first electrode 110 and therefractive index n₃ of the insulating layer 150, a user is less likelyto visually recognize a portion of the lateral side of the firstelectrode 110 in contact with the insulating layer 150. In a case wheren₄ is (n₂+n₃)/2, the aforementioned portion of the lateral side of thefirst electrode 110 is the most less likely to be visually recognized.Therefore, √(n₁×n₂)≤n₄≤(n₂+n₃)/2 indicates a condition for achievingsuperior extraction efficiency of light from the organic layer 120 andless visibility of a portion of the lateral side of the first electrode110 in contact with the insulating layer 150.

As described above, although the embodiments and examples of the presentinvention have been set forth with reference to the accompanyingdrawings, they are merely illustrative of the present invention, andvarious configurations other than those stated above can be adopted.

1. A light-emitting device comprising: a light-transmitting substrate; a light-transmitting interconnect located over the substrate; an insulating layer located over the substrate and the interconnect, the insulating layer covering an edge of an upper surface of the interconnect in a width direction; and an intermediate layer formed on at least a portion of the edge of the interconnect.
 2. The light-emitting device according to the claim 1, wherein a thickness of the intermediate layer is equal to or greater than 50 nm.
 3. The light-emitting device according to the claim 1, wherein the interconnect comprises ITO, IZO, Ag or an Ag alloy.
 4. The light-emitting device according to the claim 1, wherein the intermediate layer is disposed between the substrate and the insulating layer.
 5. The light-emitting device according to the claim 4, wherein a thickness of the intermediate layer is equal to or greater than 50 nm.
 6. The light-emitting device according to the claim 4, wherein the interconnect comprises ITO, IZO, Ag or an Ag alloy.
 7. A light-emitting device comprising: a light-transmitting substrate; a light-transmitting interconnect located over the substrate; an insulating layer located over the substrate and the interconnect; and an intermediate layer formed in at least a region of a lateral side of the interconnect that overlaps the insulating layer.
 8. The light-emitting device according to the claim 7, wherein a thickness of the intermediate layer is equal to or greater than 50 nm.
 9. The light-emitting device according to the claim 7, wherein the interconnect comprises ITO, IZO, Ag or an Ag alloy.
 10. The light-emitting device according to the claim 7, wherein the intermediate layer is disposed between the substrate and the insulating layer.
 11. The light-emitting device according to the claim 10, wherein a thickness of the intermediate layer is equal to or greater than 50 nm.
 12. The light-emitting device according to the claim 10, wherein the interconnect comprises ITO, IZO, Ag or an Ag alloy. 